1. Field Of The Invention
This invention relates to apparatus for recording a multiplicity of reactions effected simultaneously in separate vessels. The invention is particularly, though not exclusively, concerned with improving the efficiency of biochemical analyses where large numbers of biochemical tests are required to be conducted speedily and efficiently, such as in use with dispensing devices used in testing where predetermined quantities of liquid reagents are supplied to separate vessels.
2. Description Of The Prior Art
Various devices of the type with which this invention can be used have been proposed for dispensing liquid into a number of vessels. For example, it has been proposed to dispense liquid by use of a row of pipettes each having a plunger associated therewith, the plungers being connected to a common operating device which may be operated mechanically or manually to draw liquid into the pipettes and subsequently to dispense it. Examples of such devices are disclosed in U.S. Pat. Nos. 3,568,735 to Lancaster (Class 141/238) and 4,047,438 to Sekine (Class 73/423).
It has also been proposed in European Patent Application No. EP 80 30 3132, filed September 5, 1980, Dynatech AG (Int. Cl. G 01 N 21/76), to utilize a dispensing device in which liquid feed is effected using a multichannel peristaltic pump.
It has further been proposed in U.S. Pat. No. 3,696,971 to Madin (Class 222/183) to arrange for the upper ends of a number of pipettes to open into a large chamber which is subjected to reduce pressure to fill the pipettes with liquid which is then pressurized to dispense the liquid from the pipettes. A similar principle is employed in U.S. Pat. No. 3,982,438 to Byrd (Class 73/425.6) to fill the pipettes and effect dispensing except that, in this case, negative and positive pressure is applied to the pipettes through the intermediary of a flexible diaphragm.
In the recording of luminescence reactions, it has previously been proposed to utilize very sophisticated and expensive equipment in which either one test is conducted at a time using, for example a photomultiplier tube to measure the luminescence characteristics of a reaction being studied or several photomultipliers are used to monitor several reactions simultaneously. This is not only time consuming but also requires the use of expensive equipment. In order to overcome this problem, it has also been proposed to utilize a photographic technique where luminescence reactions are analysed using containers or vessels to hold the reactants and an instant photographic film to record luminescence. ("INVESTIGATION OF A NOVEL SOLID-PHASE CHEMILUMINESCENT ANALYTICAL SYSTEM, INCORPORATING PHOTOGRAPHIC DETECTION, FOR THE MEASUREMENT OF GLUCOSE" by T. J. N. Carter, T. P. Whitehead and L. J. Kricka--Talanta Vol. 29, pages 529 to 531, 1982) In such a method, tubes are placed in a mask. Then in a darkened room, a shutter covering the film is removed and the assembly of mask and tubes is placed in a film holder so as to cover the sensitive area of the film. Still in the dark, liquid is dispensed into the tubes to initiate the luminescence reaction using a syringe unit. Also, see Industrial Laboratory, Vol. 40, No. 8, February 1975, p. 1118. However, such a technique is difficult to adapt to a large number of reactions because it is effected largely in a darkened room and existing equipment would require the use of a moving shutter to expose only those reaction vessels which can be fed simultaneously with reactant. Thus, not only would a moving shutter be required but also means for indexing the dispensing device, such indexing means being arranged so that indexing of the dispensing device is effected with appropriate light shielding to prevent stray light from reaching the film.
It has been previously proposed in U.S. Pat. No. 3,627,431 to measure the extent of colorimetric reactions photographically by inserting a plurality of tubes into a holder, sliding the holder and tubes into a cabinet containing a light source and shutter in the top of the cabinet and a photographic film in the bottom of the cabinet. Energization of the light source or opening of the shutter exposes the film through the sample tubes.
U.S. Pat. No. 3,923,462 discloses apparatus for detecting the concentration of a substance in a fluid, e.g. ozone, in air, by pumping the fluid through a passage in a light tight housing past a disc which luminesces in the presence of the substance to be detected. Photographic film is continuously driven across an optical step wedge disposed on the opposite side of the passage to the luminescent disc so as to provide a continuous record of the degree of luminescence of the disc and thereby a record of the concentration of the substance in the fluid.
European Patent Application No. EP 80019786 discloses a detection device for luminescence reactions which comprises a multi-layer structure including at least one layer having a first reagent system responsive to the presence of an analyte to produce a reaction product, at least one other layer having a second reaction system responsive to the presence of the reaction product to produce luminescence, and a photoresponsive to light produced by the second reagent system.
European Patent Application No. EP 80 30 3132 discloses apparatus for detecting luminescence reactions in which a single row of pipettes and a single row of photodetectors are arranged on opposite sides of a plate carrying an array of reaction wells. The pipettes and photodetectors are mounted on a common support which is driven longitudinally of the plate carrying the array of reaction wells. Such an apparatus is expensive and complicated in that it requires careful synchronization of the various parts of the apparatus to operate correctly.
U.S. Pat. No. 4,027,979 discloses detection apparatus for colorimetric reactions in which light from a light source at the bottom of a housing is individually piped to the undersides of reaction tubes within the housing. The housing can be closed by a cover on which a film holder is provided. Probes extend from the cover in the region of the film holder into the reaction tubes to transport light from the reaction tubes to the photographic film.
European Patent Application No. 80071859 (published 16 February 1983) discloses a luminescence detection device in which an opaque reaction vessel housing defines individual reaction vessels which are closed at the top by cannula-piercable portions of the housing. The housing rests on a transparent spacer disposed above a shutter and a photoresponsive imaging layer. The reactions are initiated by liquid injected through the cannula-piercable portions of the housing.
None of the last-described six devices is of a design which lends itself to recording photographically in a simple manner of a large number of luminescence reactions which are required to be initiated simultaneously.